Short communication: Study on heavy metals (Chromium, Cadmium, Cobalt and Lead) concentration in three pelagic species of kilka (Genus Clupeonella) in the southern Caspian Sea

Environmental pollution by heavy metals has been a matter of growing concern over the last decades. Heavy metals are toxic and tend to accumulate in living organisms. In many studies, fish has been used as a sampling item to monitor the quality of ecosystems because of two reasons: 1- Fish bio-concentrate and integrate contaminant load both in time and space leading to more representative results compared to water samples, and 2- Fish represent the bio-available fraction of environmental contaminants, unlike water and sediment samples. On the other hand, humans consume fish species which makes attention to these fauna even more important. Levels of some metals in the water running in Volga River, towards the Caspian Sea, and elevated concentrations of some trace elements have been reported in sediment. Also, various pollutants have accumulated in the Caspian Sea due to effluents from coastal catchments and leakage from offshore oil production and land-based sources. ... The objective of the present study was to investigate the concentrations of chromium (Cr), cadmium (Cd), cobalt (Co) and lead (Pb) in fish muscle in the most commercially important fish species of kilka (common kilka, C. cultriventris, anchovy C. engrauliformis and bigeye kilka C. grimmi) in the Caspian Sea.